Synchronizing clock system.



J. W. BRYCE.

SYNCHRONIZING CLOCK SYSTEM.

APPLICATION FILED NOV. 16, 1918.

Patented July 2.2, 1919.

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UNITED STATES PATENT OFFICE.

JAMES W. BRYCE, OF BINGHAMTON, NEW YORK, ASSIGNOR TO INTERNATIONAL TIME RECORDING COMPANY, OF NEW YORK, A CORPORATION OF NEW YORK.

SYNCHRONIZING CLOCK SYSTEM.

Specification of Letters Patent.

Application filed November 16, 1918. Serial No. 262,757.

To all whom it may concern:

Be it known that I, JAMES W. BRYCE, a citizen of the United States, residing at Binghamton, in the county of Broome and State of New York, have invented certain new and useful Improvements in Synchronizing Clock Systems, of which the follow ing is a full, clear, and exact description.

In an application filed by me on May 21, 1918, Serial Number 235,813, I have set forth and described a new method and apparatus for controlling and synchronizing a plurality of secondary clocks by means of a master clock, and this application is for an improvement on such systems.

In the original system as set forth in the application above referred to the master clock, in addition to its other functions connected to a controlling or line circuit at definite intervals of predetermined duration a source of continuouscurrent. Each secondary clock was equipped with means for retarding and means for accelerating its rate, and two circuit-closers operated by the secondary clock movement for definite periods in fixed relation to the time as indicated by its hands to connect to line either the one or the other means, whereby, when any portion of such periods overlapped in time the period during which the master clock sent its current over the same line, this current would pass to and operate the retarding means if the clock were too fast, or the accelerating means, if it were too slow, and thus bring the secondary into exact synchronism with the master clock.

"In some systems the master and secondary clocks are wound, when necessary, by hand, in others the secondaries are periodically or continuously wound by current impulses under the control of the master clock, while in still others the secondary clocks are operated by momentary periodic impulses sent over the line by the master clock, for example, once a minute. These latter are known as impulse systems and it is to them that this invention relates.

Ordinarily in such systems the transmitted impulses are all in the same direction, or their direction is immaterial so far as their operative effect is concerned, but in the present case the synchronizing of the secondary clocks is effected through suitable instrumentalities by a change in the direction of flow of such impulses, and the manner in which I accomplish this may be thus generally described.

It may be assumed that for a given but arbitrary interval, say from the hour to forty-five minutes past the hour, the master clock sends positive current impulses to line and for the remaining fifteen minutes of each hour negative current impulses. All of these impulses actuate alike the secondary clocleclriving mechanism, and are presumed to keep it on time.

Each secondary, however, is provided with means for retarding and with means for accelerating its rate, and with two circuit-controllers which are operated by the clock to bring into operative relation to the line either of said means for definite intervals in fixed relation to the time as indicated by the hands of the secondar clocks. If the clock be on time such period s will not overlap in time the period of reverse or negative impulses from the master clock and no effect is produced, but should any portion of either of such periods overlap that of the negative current, then by means of devices responsive to such negative currents the retarding device is brought into action if the secondary be too fast, or the accelerating device if it be too slow, until the condition of exact synchronism is reestablished.

This system is illustrated in the accompanying drawing in which Figurel is a dia gram of the complete system, and Fig. 2 a sectional view of a differential gear used in a secondary clock.

The master clock may be of anyknown construction and comprises a driving train 1, a verge shaft 2, carrying a contact 3, and a minute shaft 4: having an arm 5 with which the oscillating contact 3 engages once each minute. On the hour shaft 6 is a disk 7 having two conducting segments 8, 9, set in its periphery, and upon such periphery bear two closely placed brushes or strips 10.

By the operation of the clock, the segment 8 comes under the brushes at exactly fifteen minutes of the hour, and the segment 9 under the said brushes at the even hour. From this it will result that when the brushes are on segment 8 an impulse of current flows from any suitable local source 11, through the contact 3 and an electro-magnet 12, which operates to move a ratchet wheel 13 one step, and to thereby shift to the right an insulating rod 14 supported by two nary means depending upon the position of the contacts 15, being employed for this purpose.

It will he observed that contact 3 comes into engagement with the arm 9 once each minute, and this is utilized to send from the source 12 a current impulse over a wire 19 which includes a relay magnet 20, which being thus energized attracts its armature 21 and closes a break in the main or controlling circuit 17, 18, sending thereby the impulses either positive or negative, as the case may be, that operate the secondary clocks.

In general, therefore, it will be seen that the master clock sends a current impulse to line once each minute, which impulses operate the hands ofthe secondary clocks, and that from the hour to forty-five minutes after the hour these impulses are say positive, while for the remaining fifteen minutes of each hour they are ne ative.

In the secondary cloc which is shown at the right of Fig. 1, the minute arm 22 is fixed to the post or bar 23 of the floating member of a differential gear. One of the gear members of this device 24 is fast to a hub 25, loose on the shaft 22, and the other 26 is fast to a similar hub 27. The hub 25 carries a ratchet wheel 28 which is moved step by step by a pawl 29 operated by the impulses transmitted over the line which pass through one of the opposing coils 30 of a relay. Assuming the hub 27 to be stationary, the floating member 23 of the differential is therefore rotated and carries with it the minute arbor of the clock.

The hub 27 carries a ratchet wheel 31 with which engages a long throw pawl 32 operated by a magnet or solenoid 33 and adapted by the energization of such solenoid to be turned in a direction opposite to the normal movement of the ratchet 28.

The hour shaft of the secondary clock carries a cam disk 34 which operates to shift a spring contact '35. At thirty minutes of the hour as indicated by the hands of the secondary clock the-contact 35 is forced by the high part ofthe cam into engagement with a contact 36 and closes a circuit from the stop 37 of a polarized relay 38, through the solenoid 33 and back to line wire 17. This engagement continues until fifteen minutes of the hour, as indicated by the noid 33, for at the instant of change the contact 35 has dropped off of the high part of the cam. Should the secondary be slow, however, then the engagement of contacts 35 and 36 is not interrupted until after the the instant when the direction of the line impulses changes, in which event the armature 39 being attracted, current is directed from the line through the solenoid 33, and the ratchet wheel 31 is thereby turned sufliciently to bring the secondary clock up to synchronism with the master clock when the contacts 35 and 36 will instantly separate.

At exactly the hour the cam 34 permits the contact 35 to drop onto a contact 40 and if the clock be too fast this will occur before the change in the line impulses from negative to positive has taken place. Hence the line current will flow from the stop 37 through contacts 35 and 40 and through the second of the two opposing coils 41 of the relay, and back to line, and'this impulse will neutralize the magnetizin effect of the line impulse and the relay wi l not'operate its pawl 29, normove the clock until the master clock has reversed the line impulses at the even hour. By this means the secondary clock is brought into synchronism.

In illustrating the invention I have shown specific devices for stopping the clock and for advancing its hands by one operation, but these are broadly typical of any means for retarding or for accelerating its rate of movement that may be used. In other respects the invention is not limited to the special means shown and described.

Having .now described my invention, what I claim is:

'1. In a synchronizing clock system the combination with a master clock adapted to send for predetermined intervals of definite duration current impulses of given direction over the line for the operation of secondary clocks, of one or more secondary clocks each containing means for retarding and means for acceleratin the secondary clock,.whereby the latter if out of synchronism with the master clock will be retarded if too fast or accelerated if too slow.

2. In a synchronizing clock system the combination with a master clock adapted to send for predetermined parts of given pe riods positive impulses and for the remaining parts of such periods negative impulses to line for the operation of one or more Secondary clocks, means in each for retard ing and means for accelerating their rate of movement, circuits including said means, circuit controllers for completing breaks in such circuits at definite intervals in fixed relation to the time as indicated by the hands of the secondary clocks, a polarized relay in the main line and connections between the main line and the retarding and accelerating circuits in the secondary clock, whereby on the transmission of impulses in one direction the main line will be connected to either the retarding or the accelerating means and the secondary clock, if it be too fast or too slow, brought into synchronism with the master clock.

' ntestimony whereof I hereunto afiix my signature.

JAMES W. BRYCE. 

